High light white light LED flashing circuit theory and design that the solar energy supplies power

A foreword The intersection of blinker and apparatus that this text introduce camera take a candid photograph servicing lighthouse when the vehicle overspeeds at the expressway. According to the open-air job requirements, the lighting equipment needs sufficient energy source and sufficient life time, this circuit adopts the solar energy and holds the battery-opwered way, so require the apparatus to have characteristic of static low power consumption. Compared with other lamps and lanterns apparatuses, such advantages as the white light LED has high, low power dissipation of luminance, longe-lived. This text will introduce the cipher scheme of the flashing circuit of LED lamp of high light white light that a kind of solar energy supplies power specifically, explain design and circuit static low power consumption implement method of the electric power supply, and discuss that should be paid attention to in the design process the question.

2 systems make up Fig. l is a composition block diagram of this system. Make analysis on charging protective circuit part, controlling circuit part of the blinker, white light LED protective circuit part in Fig. 1 as follows.

2.1 The solar energy charges the protective circuit 2.1.1 Solar energy panel The solar energy panel not only can offer the electric energy in the daytime, but also can also offer the electricity at the night. The solar energy panel is the same as transistor-resistor logic, composed of semiconductors, the main material is silicon, also there are some other alloy. The surface of the solar energy panel is made up of two parts with different property. When illuminating by the light, can change the light energy into the electric energy, make the electric current flow into another party from one party. So long as solar energy panel is illuminated by the sunshine or light, can generally send out and equivalent to light energy 1/10 electric energy received. In order to make the solar energy panel reduce optical reflection to the maximum extent, change the light energy into the electric energy, generally covering with one layer and preventing all reflected membrane above, make the surface of the solar energy panel purple. Solar energy power some mainly by the solar energy panel photovoltaic assembly , charging circuit and storage battery make up. The photovoltaic assembly absorbs the illumination in the daytime, turn the solar energy into the electric energy to store in the solar battery. When it is generally fine, under the ideal illumination intensity, it needs only 4 hours to fully charge. This system adopts 15 V solar energy panel, it is 17V- 20V to measure the service voltage of both ends of the panel actually, the charging current is 200mA- 800mA. 2.1.2 The accumulator battery capacity is designed The energy storing device of the power system of solar battery is mainly a storage battery. The storage battery related to square matrix of the solar battery usually works under the floating-charge state, its voltage is changed with the change of electric energy production of square matrix and electricity consumption of the load. It is much bigger that its capacity ratio supports the required electric quantity. The energy that the storage battery offers is still influenced by ambient temperature. In order to match with the solar battery, require the storage battery to work longe-livedly and maintaining simply. 1Application of the storage battery Can be numerous with the storage battery kind of corollary use of solar battery, adopt extensively have the intersection of lead acid and maintenance-free battery, ordinary lead-acid battery and alkaline the intersection of Ni-CD accumulator and 3 kinds at present. China mainly uses the lead acid maintenance-free battery, because its inherent ” exempts ” at present Safeguard characteristic and of low more pollution characteristic to environment, very suitable power system of solar energy used for reliable performance, especially the work station of the unattended operation. Because ordinary lead-acid battery needs maintaining frequently and environmental contamination is relatively great, mainly suitable for safeguarding ability or low-grade occasion use. Though alkaline Ni-CD accumulator has better low temperature, overcharged, overfall characteristic, but because of its great of price, are only suitable for the comparatively special occasion. 2Calculation of the accumulator battery capacity The capacity of the storage battery is very important to guaranteeing to supply power continuously. Within one year, each there is difference greatly in month in the electric energy production of square matrix. The electric energy production of square matrix is in unable to be satisfied with required month for electricity consumption, fill the electric energy of the storage battery; Exceeding required month for electricity consumption, store the surplus electric energy by the storage battery. So deficiency and surplus value of the electric energy production of square matrix, it is one of the bases of confirming the battery capacity. Likewise, the load electricity consumption during it is overcast and rainy continuously must be obtained from the storage battery too. So, the electric consumption during this time is one of the factors of confirming the battery capacity. So, the capacity Bc formula of the storage battery is:

In the type: A is the safety coefficient, while fetching 1.1- 1.4; QL is the daily average electric consumption of the load, multiplied by the number operating hour of Japan for the working current; NL is the longest serial overcast and rainy days; To is the correction factor of the temperature, generally fetches l at over 0 , -10% of the the above fetches 1.1, – under 10 fetches 1.2; Cc is the depth of discharge of the storage battery, the general lead-acid battery fetches 0.75, the alkaline Ni-CD accumulator fetches 0.85. Require through calculate, choose the intersection of 12 V and the intersection of 8 Ah and ordinary lead-acid battery according to system this. 2.1.3 Charge the protective circuit The solar energy is charged the protective circuit to protect two parts to make up by overcharged and overfall. It is protected that overcharged: When the solar energy is stiff to charge storage battery, make the output voltage of the storage battery exceed 14.5 V, the overcharge way control relay makes the solar energy panel stop charging. When the output voltage of the storage battery falls back to 14 V, the solar energy panel charges storage battery again. Overfall is protected: When the output voltage of the storage battery is lower than 10.5 V, the storage battery stops the outward electrical supply. When the accumulator voltage exceeds 10.5 V, the outward electrical supply again. It is made up of two operation amplifiers to charge the protective circuit, the circuit is shown as in Fig. 2. Vi1, Vi2 are the output voltage of the storage batteries in Fig. 2, Vref is the comparative reference voltage of the operation amplifier, its concrete value is presumed by users according to different requirements. In the real design process, should notice feedback resistance is chosen in Fig. 2, the greater feedback resistance is, control and output the the smaller difference of going back of correspondent input Vi.

2.2 Controlling circuit of the blinker The controlling circuit needs to carry on different designs according to different requirements. Change the complicated controlling circuit and use MCU one-chip computer to control as to the flashing function, control the convenient, simple, stability like this. Because this system design only requires the blinker to glimmer regularly, the function is single, so adopt the simple pure hardware circuit implementation. The circuit makes up and is shown as in Fig. 3.

2.2.1 Pulse-generating circuit This circuit adopts 4047 pulse generators, 4047 outside is simple in construction, the characteristic is steady, and the quiescent power drain is extremely low static measured value is 0.5 mA . 4047 outcoming signals, as the trigger impulse of the ferquency dividing circuit, the frequency of its outcoming signal is connected electric capacity and resistance control. 2.2.2 Ferquency dividing circuit